SunShot Looks To Close The Solar Efficiency Gap

The U.S. Department of Energy’s solar-power initiative is offering up to $12 million in new research funding aimed at closing the gap between today’s solar cell efficiencies and the “Shockley-Queisser Limit,” which says that typical single-junction photovoltaics can convert no more than 33.7 percent of the sun’s energy into electricity.

This effort, with the oh-so-sexy name “Foundational Program to Advance Cell Efficiency II (FPACEII)” isn’t limited strictly to silicon-based technologies; work with thin-film materials such as cadmium telluride (CdTe) and cooper indium gallium diselenide (CIGS) is also eligible.

As the “II” after the program’s title indicates, this a second round of funding. The first round doled out $35.8 million to 18 different projects, mostly based at universities or research centers.

“In the current solicitation, FPACEII seeks proposals from collaborative teams of researchers from national laboratories, universities, and industry that can develop materials model systems and fabricate prototype devices that achieve efficiencies near the Shockley-Queisser limit,” the Department of Energy said.

The overall goal of the SunShot program is to make solar energy cost-competitive with other forms of energy by the end of this decade. By the DOE’s reckoning, the means driving the price of solar electricity to about 6 cents per kilowatt-hour on a levelized cost basis (that is, over the lifetime of a system).

In the Obama administration’s first term, the Solyndra bankruptcy became the public face of its renewable energy efforts, obscuring the wide range of research and development going on with SunShot.

In addition to the Foundational Program, SunShot supports next generational photovoltaics – things like multijunction cells and novel materials; has an incubator program for startups; is backing a big initiative to improve manufacturing processes; and is seeking to trim the “soft costs” – everything outside the hardware – of going solar.

As for solar efficiency, the topic can be rather confusing because each category of PV – and there are dozens of them – has its own possibilities and thus rankings. So it’s not uncommon to hear reports of new records being set that are lower than the previous one. The National Renewable Energy Laboratory chart pictured above, and available here on the lab’s website, is a great source for keeping things straight.